It is predicted that in the future, large-capacity loads and distributed power supplies are going to increase, a room capable of being controlled by a power supply company side (power system side) is going to be small, and the power system will overall become very unstable wherein the large-capacity loads includes, for example, an electric automobile, the occurrence of the demand thereof being difficult to predict and the distributed power supplies includes, for example, a photovoltaic power generator, the occurrence of the demand being also difficult to predict. In order to control the unstable power demand and supply thereof, various EMSs (energy management systems) such as a CEMS (Community Energy Management system), a BEMS (Building Energy Management System), a HEMS (Home Energy Management System), and a FEMS (Factory Energy Management System) are proposed.
They have a main object to achieve leveling of a demand and supply and energy saving in an independent small-scale power system under management by carrying out the output increase and decrease control of distributed power supplies, suppression of a demand of power equipment, and suppression of abrupt variation and peak shift in the case of possessing energy storage equipment (a stationary storage battery, a heat storage tank and the like). For example, JP-A-2008-236904 (Kokai) proposes the example of the BEMS that performs energy management of a building, and JP-A-2009-130985 proposes the example of the HEMS that performs energy management in a household.
Further, as the system that aids interchange of power among a plurality of independent small-scale power systems, JP-A-2011-61970 (Kokai) and the like are proposed. JP-A-2011-61970 (Kokai) proposes a system which reserves power interchange amounts among respective systems in each time in advance, temporarily converts an AC power into a DC power in an interconnection line of each of the systems and interchanges power with each other.
In a conventional power system, the highest priority is placed on the necessity of complying with a supply-demand balancing rule at each unit time zone, and therefore, as for power, the system side (power supply company side) has generally set up a plan which is entirely systematic, and conducted control. When EMSs are interconnected with each other from an upper layer to a lower layer, for example, in the CEMS (Community Energy Management System) that controls a system side, and the BEMS, HEMS, FEMS and the like that control a user side such as each building and households, the operation of each EMS is independent, and the influence of the power demand/supply which occurs in the range managed by the BEMS, HEMS, FEMS and the like of the lower order is only unilaterally estimated and controlled in accordance with the demand prediction by the CEMS of the upper order. The method for creating the plan of the power amount (electric energy) interchanged at each time (hereinafter, called a power delivery and reception plan) by utilizing the power storage equipment of a partner by cooperating with each other among EMSs is not considered. For example, the above described JP-A-2011-61970 proposes the system which reserves/agrees the power interchange amount among the systems at each time in advance among a plurality of independent small-scale power systems and interchanges power with each other, but the mechanism is such that the power delivery and reception plan is on the preconditions that the system side which issues a reservation creates the entire plan, and after creation, agreement of the partner side is obtained.
When close interconnection accompanied by power delivery and reception from each other is to be carried out among the EMSs which are independent from each other, it is predicted that if the EMSs set up the plans of power delivery and reception independently from each other, interconnection with integrity of the plans being kept is difficult because the plans differ from each other in temporal grading, and the mechanism which solves this is required.
When it is assumed that the distributed power systems which the EMSs each manages includes power storage equipment with a large capacity as a buffer, regulation in a time direction of the over-and-under amount of the power amount per unit time becomes easy, and therefore, the temporal gradings of the power delivery and reception plans which are required among the EMSs which are independent from each other are likely to differ significantly. For example, it is assumed that in a building A which includes power storage equipment with a large capacity, as long as the balance of the electric power which is interchanged from outside is kept in the unit of an hour, the electric power is within the range capable of being regulated with charge and discharge of the stored power amount, and there arises no problem, whereas in a building B which does not include power storage equipment, the total amount of the balance of the electric power which is interchanged from an outside has to be kept at each instant. When electric power is interchanged between the buildings A and B as above, if a reservation of a request or a supply of electric power is made by the building A side, the B side needs to set up a power delivery and reception plan for each unit time zone which is executable based on the request of the building A side. As this example, it is predictable that when close interconnection is to be carried out among the EMSs which are independent from each other when the supply-demand balancing rule at each unit time does not have to be kept, interconnection becomes difficult because the temporal gradings of the mutual plans differ from each other.
Furthermore, it is difficult to consider that the EMSs are introduced simultaneously from the upper layer to the lower layer, and it is predictable that, for example, after the BEM (Building and Energy Management System) which controls the power demand and supply of each building is put into widespread use, the CEMS which conducts centralized control over the BEMS is introduced. Further, it is predictable that some of the EMSs of the hierarchy go down due to an accident or a failure. Therefore, the mechanism of power delivery and reception scheduling for autonomous and distributed EMSs, which operates without a problem even if the EMSs are introduced stepwise from the EMSs of the lower layer, and are capable of interconnecting with each other afterwards.